Rename ThemeVariant to Theme (#3252)

This PR renames the `ThemeVariant` type to `Theme`.

This better reflects its purpose, as well as matches the same name as we
had before, which should make porting crates slightly easier.

Release Notes:

- N/A

crates/editor2/src/display_map.rs

@@ -21,7 +21,7 @@ use lsp::DiagnosticSeverity;
 use std::{any::TypeId, borrow::Cow, fmt::Debug, num::NonZeroU32, ops::Range, sync::Arc};
 use sum_tree::{Bias, TreeMap};
 use tab_map::TabMap;
-use theme::ThemeVariant;
+use theme::Theme;
 use wrap_map::WrapMap;
 
 pub use block_map::{
@@ -505,7 +505,7 @@ impl DisplaySnapshot {
         &'a self,
         display_rows: Range<u32>,
         language_aware: bool,
-        theme: &'a ThemeVariant,
+        theme: &'a Theme,
     ) -> impl Iterator<Item = HighlightedChunk<'a>> {
         self.chunks(
             display_rows,

crates/editor2/src/editor.rs

@@ -81,7 +81,7 @@ use std::{
 pub use sum_tree::Bias;
 use sum_tree::TreeMap;
 use text::Rope;
-use theme::{ActiveTheme, PlayerColor, ThemeColors, ThemeSettings, ThemeVariant};
+use theme::{ActiveTheme, PlayerColor, Theme, ThemeColors, ThemeSettings};
 use util::{post_inc, RangeExt, ResultExt, TryFutureExt};
 use workspace::{ItemNavHistory, SplitDirection, ViewId, Workspace};
 
@@ -9962,7 +9962,7 @@ pub fn highlight_diagnostic_message(
     (message_without_backticks, highlights)
 }
 
-pub fn diagnostic_style(severity: DiagnosticSeverity, valid: bool, theme: &ThemeVariant) -> Hsla {
+pub fn diagnostic_style(severity: DiagnosticSeverity, valid: bool, theme: &Theme) -> Hsla {
     match (severity, valid) {
         (DiagnosticSeverity::ERROR, true) => theme.status().error,
         (DiagnosticSeverity::ERROR, false) => theme.status().error,

crates/editor2/src/items.rs

@@ -27,7 +27,7 @@ use std::{
     sync::Arc,
 };
 use text::Selection;
-use theme::{ActiveTheme, ThemeVariant};
+use theme::{ActiveTheme, Theme};
 use util::{paths::PathExt, ResultExt, TryFutureExt};
 use workspace::item::{BreadcrumbText, FollowableItemHandle};
 use workspace::{
@@ -777,7 +777,7 @@ impl Item for Editor {
         ToolbarItemLocation::PrimaryLeft { flex: None }
     }
 
-    fn breadcrumbs(&self, variant: &ThemeVariant, cx: &AppContext) -> Option<Vec<BreadcrumbText>> {
+    fn breadcrumbs(&self, variant: &Theme, cx: &AppContext) -> Option<Vec<BreadcrumbText>> {
         todo!();
         // let cursor = self.selections.newest_anchor().head();
         // let multibuffer = &self.buffer().read(cx);